Solution.java

import java.util.Scanner;

class UsernameValidator {
    public static final String regularExpression = "^[a-zA-Z][\\w]{7,29}$";
}

public class Solution {
    
    private static final Scanner scan = new Scanner(System.in);

    public static void main(String[] args) {
        int n = Integer.parseInt(scan.nextLine());
        while (n-- != 0) {
            String userName = scan.nextLine();

            if (userName.matches(UsernameValidator.regularExpression))
                System.out.println("Valid");
            else 
                System.out.println("Invalid");
        }
    }
}